Method of waterproofing vulcanized fiber



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EMIL E. NOVOTNY AND CHARLES J. EOMIEUX, F PHILADELIBHIA, PENNSYLVANIA,

AbSIGNURS T0 JOHN STOGDELL STOKES, 0F SPRING VALLEY is, nomine- DOhl' 'VLEY POST OFFICE, PENNSYLVANIA.

METHOD OF WATERPROOFING.VULCANIZED FIBER.

No Drawing.

This invention relates to a method of waterproofing vulcanized fiber, viscose and similar materials of celluloseorigin which are thereby formed into sheets or plastic materials.

More particular] stated, this-invention comprises a metho of treating fibrous materials which'have been previously impreg 1,398,146, issued November 22, 192 1, and the co-pending application of Novotny and Ken dell, Serial Number 501,273, filed September 17, 1921. Tu this patent and the application referred to there have been shown several useful forms of phenolic condensation products which are particularly well suited for this purpose.

vThe step of impregnating or incorporating in thefibrous structurea suitable cementi 'tious binder-which is not'subsequently altered or dissolved out of the structure by the converting agent acting upon the cellular material, ermits ot an intimate combination of binder with the eventually altered cellular structure after it has been treated as inthe well-known art of papervulcanination. lit is already well-known in" the art that cellular structures may. be altered b various means as in the reduction of camzed fiber or viscose.

or example, when vulcanized fiber is produced the cellulose tissue is gelatinized or subjected to hy drolysis in the presence of amaterial such as zmc chloride. Other steps, of course, can be utilized, such as, for example, a treatment with cold sulphuric acid or cupro-ammohium solution. As the art of altering cellulose bodies into jellylike or gelatinous. substances is well-known, it does not require further mention here.

We are aware,- also, that it has been proposed to impregnate vulcanized fiber with' a phenolic condensation product after such vulcanized fiber had been formed. This, however, is not the nature of'our improvement. It has been found practically impossible-to thoroughly and properly impreg Applieatlon filed September 4, 1923. Serial No. 660,952.

nate a sheet. of vulcanized fiber inasmuch as the material is non-porous or has more ot the characteristics of a gel and therefore the resin cannot be absorbed by the material.

We hnd, however, that where a sheet of paper is impregnated with a varnish or' resinous body and is not pressed orcompactcd to a greater extent than necessary to remove surplus material, the paper or sheetlike'structurc will be capable of absorbing large quantities 0t water, and this to a much vgreater extent than if the fiber or cellular structure were elatinized or al tered as by hydrolysis in t e vulcanized fiber process. This facility of the resin imprcg nated or incorporated sheet of taking up.

various quantities of water makes it possible to introduce therein the modifying medium such as zmc chloride which causes the hydrolysis of the sheet, and which theretore, after the zinc chloride is removed, results in an intimate mixture of gclatinized or altered or hydrol zed cellulose and binder, reinforcing me ium, or water-proofingagent thereton 7 Likewise this method permits of the treatment of thicker sheets of pa er than would be possible if the waterproo ng material or binder were to be introduced subsetiuently by impregnation into the previous y hydrolyzed cellulose. Likewise, thick sheets of'laminated fiber can be produced rapidly with only a short washing operation inasmuch as such sheetscan be treated practically on a continuous process machine, and

after being dried they may be cemented togetherby the coatingof the binder on the surface or the cementing action of the incorporated binder coming to the surface upon being formed as by the combined action 0 7 heatandpress urer 1 Y v To make our method clear it may be stated thatthe fiber such as paper, cloth or other cellulose material is impregnated with the durite, dissolved in a suitable solvent such as, for example, alcohol, this solution being of I. proper strength to givethe ercentage of impregnation desired. The s eet may be dried but preferably this operation is dispensed with. The web is submerged in a water bath which removes therefrom to be thoroughly .105 the excess alcohol and causesthe fibrous body web is now run into another vat containing the zinc chloride solution which penetrates into the fibrous structure very readily be cause of the aiiinity it has for the Waterpres ent in the fiber, and the fiber is thereby quickly hydrolyzed. The web is subsequently washed to remove the zinc chloride or other altering media, is dried at low tem perature, and may be rolled to be Subsequently cut into sheets or used in any desired manner.

As another example of incorporating the binder or resinous body with the fibrous cel lulose material, we can proceed as follows:

To the paper pulp in the heatersis added a suitable percentage of resinous material which may be caused to'be dissolved in the alkaline water present in the heaters, or such resinous material may be added to the pulp after having been previously dissolved in a suitable solvent. After a beating of say from five minutes to one hour, or as may be deemed desirable for the particular end product to be obtained, we adda suitable precipitant, for example, ammonium sulphate. Since the precipitate thus formed is very bulky, it is widely 7v dispersed and readily clings to the fiber. The beaten mass of fibers is now'in suitable condition to be transferred to the sheet forming device or paper making machine Where it is formed into sheet-like products of various thicknesses in the usual and well-known manner. The sheetsmay bedried and rolled for subsequent hydrolyzing treatment or, if sufficiently, strong in their wet condition, the,

operation of forming the sheet and hydrolyzing may be a continuous process.

This laminated composite body may be rolled betweenheated rolls or pressed as between the platens of. a heated press to produce products of various degrees of hardness. When a binding material such as a potentially reactive resin, as, for example, durite, is used, the resin maybe cured under heat or under the combined action of heat and pressure so that it assumes its final infusible form. When this is done the product is ofa hard, tough, and moisture-resistant nature. In this form it is well adapted for and electrical arts.

being molded into various shapes and forms and may be used for the purpose of making bodies of sheetlike form or the mechanical Inasmuch as the fibrous structure has been altered to a non-porous, non-fibrous body, and-inasmuch as the binder is very thoroughly distributed throughout thestructure, the, products u n being formed, as under the action of eat and lpressure, do

ossess characteristics radica y difl'erent om products where ordinary unaltered paper or cloth is; impregnated. with a resinous body such as durite oranen'deavor is made to partially impregnate thm sheets pf vulcanized fiber with a varnishlike solution of such resin.

ordinary laminated phenolic condensation .products, thematerial does not have the paper-like structure or basis but assmnes' rather a hornlik'e and tough structure. It is, therefore,nadmirably suited in themechanical arts where great toughnessand strength are desired as an improvement on gear '-blank's, etc, made of ordinary vulcanized fiber or laminated phenolic products of either paper or cloth. Furthermore, this materialpunchesand shears cold more readily so that thicknesses of. A and over can be thus economically produced. The machining operations can likewise be more advantageously handled in a product Where the compared to the fibrous structure has been altered as by'vulcanization.

We do not limit ourselves specifically tca sheet like body inasmuch as it is readily understood that this product could be otherwise formed or comminuted into pbwdery form or that the fibrous or cellular material could be operated onin comminutedform and that the basis of impregnation before the conversion of the product to its hydrolyzed form would hold true even in these powdery materials.

show greatertoughness and permit machin- We find that. articles molded from this type of powdery material ingv operations to .a much greater degree.

The product is very compact and cantherefore be easily handled in the molds and diesi It will readily be understood that in place can be employed, such as wood flour, corn cob cellulose, cloth and woven structures, etc; Where we have herein described in the two examples methodsof introducin durite',

which is a condensation product of rfural, we wish it to be understood that other synof paper other structures formed of cellulose 'thetic resinous materials or phenolic con,

densation products may be used, such as those of formaldehyde, acetaldehyde, etc.

Further more, we do not limlt ourselves to the precise steps or method disclosed inasmuch as other equivalent methodscould be used or some of the steps could be'eliminated. For example, it is preferably,.,but not essential, to wet the sheet prior to introducing-it into the vat containing, the vulcanizing or altering medium; or, if

- preferred, the resinous bodyycould be simply as starch or-gelapurpose for-certaln' uses.

the cellulose structure and subsequently treating such structure with a cellulose altering agent.

- 2. The herein described 'method ofivater proofing or reinforcing cellulose which comprises introducing a phenolic condensastructure with-a cellulose altering agent, v

tion product into the cellulosestructure and subsequently treating such structure with a cellulose altering agent.

3. The herein described method of waterproofing or reinforcing cellulose which comprises introducing a condensation product of phenol and furf ural into the cellulose structureand subsequently: treating such structure with a' cellulose altering agent.

4. The herein described method of waterproofing or reinforcing cellulose which.

comprises introducing a resinoid phenolic condensation product into the. cellulose structure, then treating such structure with a cellulose altering agent and then heating the same to convert the condensation'product into its infusible state.

5. The herein described method of water- I proofing or reinforcingcellulose which comprises impregnating or incorporating a resinoid phenolic condensation product into the cellulose structure, then treating such and then heating and pressing thesame to convert the condensation product and the cellulose body into a hard, strong and infusible structure.

6. The herein described method of waterproofing or reinforcing cellulose which comprises introducing a synthetic resinous body or waterproofing agent into the cellulose structure, subsequently treating such.

.'l v treating such structure with a cellulose altering agent forming a body of laminated sheets so treated and heating and pressing the same to form a laminated body and therebylikewise waterproofing and reinforcing the same.

Signed at Philadel hia, and State of Pennsylvania, this 1st ay of September, A. D. 1923.

EMIL E. NOVOTNY. CHARLES J. ROMIEUX.

Philadelphia, in .the'county a 

